Starting apparatus for electric motors.



. I ATTORNEY H. 0. JAMES. STARTING APPARATUS FOR ELECTRIC MOT-0R5.APPLICATEION FILED FEB. 2!, 1911.

1,175,358. Patented Mar. 14,191

WITNESSES: VENTOR UNITED STATES. PATENT onnicE.

HENRY D. JAMES, 015 PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WEST'QLNGHDUSEELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

STARTING APPARATUS FOR ELECTRIC MOTORS Application filed February 21,1911.

To all whom it may concern Be it known that I, HENRY D. JAMES, acitizenof the United States, and a resident of Pittsburgh, in the countyof Allegheny and State. of Pennsyli'ania, have invented a new and usefulImprovement in Starting Apparatus for Electric Motors, of which thefollowing is a specification.

My invention relates to automatic devices for progressively shortcircuiting or cutting out resistance which is primarily included in thecircuit of an electric motor, and it has for its object to provide acontrol apparatus in which a plurality of switches are connected to therespective sections of a resistor and are provided with means forregulating the short circuiting of the resistor sections, as theelectromotive force of the motor builds up and the current correspondingly decreases, which shall be operative without the employmentof relays or interlocking connections.

The single figure of the accompanying drawing is a (liagram of a motorand control circuits constructed and combined in accordance withmyinvention.

The energy for operating the motor 1 of the system shown is suppliedfrom conductors 2 and 3, through fuses i and 5 and a manually operatedswitch 6. Normally connected in series with the armature 7 andseries'field magnet winding 8 of the motor 1 is a resistor 9 comprisingthree sections 10, 11 and 12 which are successively and automaticallyshort circuited by means of switches 13, 14 and 15, the stationarycontact terminals 16, 17 and 18 of the several switches being connectedto suitably spaced,

points in the resistor in order to cooperate with movable contactterminals 19, 20 and 21 in successively short clrcuiting the resistorsections at such points. The movable contact terminals 19, 20 and 21 areperinanently connected in serieswitheach other and to one 'terminal ofthe resistor 9 and also to one terminal of the shunt winding of themotor 1. Each of the stationary contact terminals is connected thisoperating coil 23 of the switch to w A belongs, to one terminal of theshunt field magnet Winding 22 and to one terminal of the armature 7 ofthe motor 1.

. The switches 13, 14 and 15 are severally Specification of LettersPatent.

Patented Mar. 14, 1916.

Serial No. 609,943.

provided with coils 24 that are wound to act in opposition to theoperating coils 23 and are connected in series with each. other from thesupply conducthr 3 to the terminals of the resistor and the shunt fieldmagnet winding of the motor 1 which are connected together.

Each of the movable contact members 1E), 20 and 21 of the switches 13,14 and 15 is connected to and operated by a core or armature 25 which issubjected to the magnetic field produced by'the corresponding coil 23. Acore or armature 26 for the corresponding coil 24 is connected to thecore or armature 25 and an adjustable armature or core 27 is alsoprovided in order to adjust the force exerted by the coils 24 inopposition to that exerted by the closing coils 23.

The closing coils 23 are connected in multiple. circuit relation withdillerent proportions of the resistor 9 included in the circuitbranches, consequently the potential at the terminals of the severalcoils is un-- equal and these coils may be uniform in construction andwill tend to close the switches in a predetermined sequence. Theactual'time at which each switch is closed and the time intervalsbetween the closure of the switches may be varied as desired byadjusting the core members'fl'i which are influenced by the opposingcoils 24 It is therefore evident that the sequential closure of theswitches is primarily independentof the ad ustable cores and that thelatter are provided for the purpose of adjusting; the

forces exerted by the opposing cells.

In the operation of the apparatus hereinbefore described,'when theswitch 6 is closed to start the -motor- 1, the counter-electromotiveforce of the motor-will be a mini-' the core 26 by the coi'l 24, andthus closes the switch 13 to short circuit the resistor section 10.

As the counter-electromotive force of the motor 1 continues to buildup,- the electromoti e force, to which the coil 23. of the switch 14 issubjected, increases until the switch 14 is closed, to short circuit theresistor section 11. As the counter-electromotire force of the motor 1increases still further with its increasein speed, the increasedelectro-motive force upon the coil 23 and the diminished current in thecoil 24 of the switch 15 will cause the said switch to close and shortcircuit the resistor section 12, thus ries therewith, a plurality ofswitches for excluding the resistance step by step, simi- -lar closingcoils for the several switches connected across the motor circuit inmultiple relation with one set of corresponding terminals connected todifferent points in said starting resistance whereby the switches tendto closesequentially, a core member on each switch influenced by itsclosing coil, a plurality of opposing coils for the several switchesconnected in series relation in the purpose of insuring sequen motorcircuit and an independent adjustable core member for each switchinfluenced bythe opposing coil pertaining thereto.

2. A control system comprising an electric motor, a starting resistanceadapted to be connected in series therewith, a lurality of switches forexcluding the 'IESlStRIiCB step by step, closing coils for the severalswitches, connected across the motor circuit in multiple relation, adifferent proportion of said resistance being included in each branchwhereby the switches tend to close sequentially, a plurality" ofopposing coils for the switches connected in series relation in themotor circuit and an adjustable magnetizable core member influenced byeach opposing coil. V v

3. A control system comprising an electric motor, a starting resistor inseries therewith, a plurality of switches for excluding said resistorstep by step, means for closing said switches in sequence in accordancewith the counter electromotive force values of said motor, said 'meanscomprising a series 0 uniform coils connected across the motor circuitin multiple relation with one set of corresponding terminals connectedat different points in. said starting resistor, means for opposing theclosing of said switches in accordance with the current traversing saidmotor circuit, said means comprising a plurality of coils in series withsaid motor, and

adjustable means for varying the effect of said series coils.

In testimony whereof, I have hereunto subscribed my name this 31st dayof Jan. 1911.

HENRY D. JAMES.

\Vitnesses I3. B. HINns, .T. V. Bnowx.

